Friday, 20 September 2013

DIY Longtail Cargo Bike - Chapter 2

DIY Longtail Cargo Bike - Intro

Did you miss out on Chapter 1?

It has been 3 weeks since my last posts and I have learnt that:

  1. TIG welding is not for the faint hearted and perhaps( if you don't have £200 to spend on a HF TIG welder ) probably best left to the pros.
  2. ALWAYS wear gloves when doing metal work. A slipped hacksaw resulting me cutting my right hand middle finger to the bone (flakes of bone scrapped of on tubing), thank goodness I didn't hit any tendons.
  3. Working out the geometry of the frame even when most of it has been done for you already is still tricky for example figuring out the bottom bracket height took a few goes, and the seat tube had ended up leaning back too far for my liking, but you can't cut and re-weld too much especially with metal this thin.

 DIY Longtail Cargo Bike - Onwards

So having abandoned the TIG welder, I have just been cracking on with the gasless mig, which has resulted in some frighteningly ugly welding. Still hopefully it will function OK.

So here she is. Bag of spanners.

Welds are looking as terrible as ever.

I have used an ad-hoc 5 bar gate sort of design for the main tubing.

For the racking I am using some mild steel tubing which I have salvaged from a toy high chair! Will I die in a ball of flames. Watch this space.

One of the trickiest bit to do was joining the new rear half near the top of the seat tube. As you can see below there was a lug available to weld on too. The normal tubing will melt through when welding.

As you can see I have a fairly large overhang at the rear of the bike. I may add in some extra support for this, tubing down to the seat stays for example but as it is it is probably more than strong enough.

Despite lining up the frame as carefully as possible, at one point I noticed the front of the bike (ie the original frame) was way out of line with the rear segment. So I propped the bike on some logs and jumped up and down on top of it to straighten it out. Seems to have worked.

DIY Longtail Cargo Bike - What is next?

Next on the list is to put some foot rests on level with the chain stays, and then to check over all of the weld to make sure that they are finished off to the best of my ability. I may use some two part filler to go over the visible welds to spare my embarrassment.

I will need some extra support for the rear racking, attaching it to the centre tube may be enough.

As mentioned in chapter one I thing; I left too much chainstay attached to the bottom bracket, which has restricted my choice for tires, I have purchase some 2.00" CST tyres for testing, and they just fit. So no 2.35" Big Apples for me. boo hoo.

The cabling is going to be fun, but a standard brake cable is just about long enough to reach the rear brake. Not sure how well an rear mech is going to work running through 2 meters of outer!

Go to Chapter 3

Sunlight and Daylight Assessment

Desktop Study 

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